Monitor Description

To monitor the fuel pump circuit, the ECM checks the fuel pump control signal (FPC) and diagnostic signal (Dl). The FPC voltage varies between approximately 0 V to approximately 12 V (duty signal). Based on the condition of the fuel pump ECU malfunction, the Dl voltage varies between approximately 0 V and approximately 12 V. The ECM then compares the variance of the FPC voltage and Dl voltage, and determines if the fuel pump circuit is malfunctioning. When the ECM determines that the fuel pump circuit is malfunctioning, a DTC is stored immediately.